1. Field of the Invention
This invention relates in general to improvements in rock bit assembly and in particular to improvements in securing rock bit sections during welding.
2. Description of the Prior Art
Rotary rock bits used for oil well drilling are commonly manufactured in three sections which are then welded together to form the completed rock bit. During the welding process the rock bit sections are supported and held together by a fixture that includes three clamping jaws, each jaw supporting one rock bit section.
When solid clamping jaws are used, the outer surfaces of the rock bit sections have to be machined to provide an area against which the chuck jaw can contact. U.S. Pat. No. 4,054,772 (Lichte) discloses such a fixture. In order to eliminate the necessity of machining the outer surfaces of the sections, the clamping jaws may be made resilient.
In U.S. Pat. No. 4,098,448 (Sciaky et al.) the desired resiliency was provided by a composite structure of a helical spring and several bellville springs. Unfortunately, the residue given off during the electron beam welding process tends to settle on the sliding surfaces. After the residue builds up sufficiently to restrict movement of the sliding member, the clamping jaw performs like a solid chuck jaw.